sustainable energy

Although the 4km-deep hole drilled by Trias Westland provided a ‘wealth of data’, the extraction of sustainable heat from the Trias layer is not sufficiently profitable. The organisation has therefore decided to fall back on Plan B and extract warm water from the Lower Chalk layer. This option is anticipated to deliver 19 to 22 MW, which is not enough to supply all the growers that have committed themselves to this project with geothermal heat.

A core of 30 metres of stone was brought up in the last specimen extracted from the drill hole. A study of this core revealed that the porosity (permeability) of the rock from the Trias layer was zero. This means that the flow of water at this depth is very difficult, if not impossible. Additionally, traces of gas were discovered in the pores of the sandstone, rendering the performance of a normal well test using a pump impossible. “An enormous disappointment,” says Floris Veeger, project manager for geothermal heat of Trias Westland. This prompted a decision to close off this deep section with two concrete plugs and to extract heat from the shallower Delft sandstone layer, in line with the other projects in the Westland area. This was disappointing for the participants and initiators, because no new layer of soil was made accessible that would help phase out the dependency on natural gas in the province of Zuid-Holland.

Well test

The Delft Sandstone Layer is nevertheless thicker and more permeable than anticipated. Apart from this, an additional layer of sand (at a greater depth) was discovered, which will not be used for this project, however. The organisation expects to extract water of a temperature of 85 to 90 degrees from the Delft Sandstone layer, at a depth of 2.3 km. The first well test is expected to take place next weekend. If, after this, the definitive decision is made to drill the second well, a second well test will take place at the end of April which will provide more information about the exact heat yield of the geothermal project. To be able to provide all participants with sufficient geothermal heat, a second doublet will be necessary. Director Marco van Soerland does not exclude that Trias Westland will do this, even though no concrete plans have been drawn up for this purpose. The potential yield in geothermal heat from the Lower Chalk layer in the Westland area is estimated at 300 to 400 MW.

Thanks to high production levels, a reduction in the use of crop protection agents, the reuse of waste materials and a low percentage of food waste, the Dutch agricultural industry has the smallest ecological footprint in the world. So concludes ABN AMRO in its online publication Agrarisch: circulair van huis uit, loosely translated as ‘The agricultural industry: circular from its very roots’.

The ABN AMRO bank has compiled a list of the cleanest and most polluting countries in the fields of agriculture. Nevertheless, Jan de Ruyter, sector banker at the Dutch Central Bank, confirms that it is almost impossible to rank all crops. “A great deal of research has been done, but this is highly fragmented. It is only when you put all the studies together that you are able to draw a coherent conclusion.”

Little waste

ABN AMRO’s claim that the Netherlands has the least polluting agricultural industry is based – among other reasons – on the high labour productivity, the limited use of chemical protection agents and antibiotics. The decline in the number of chemical protection agents used and the use of antibiotics has its roots in the strict legislation imposed by the Dutch government. Dutch legislation has therefore produced the desired effect with regard to curbing pollution within the agricultural industry.

Smart farming

In addition to this, the industry has been making use of residual and waste flows for many years. As such, a very limited quantity of raw materials is lost. Waste is also combated by making frugal use of raw materials and efficient food production. This efficient cultivation method owes its success partially to the use of sensors and data analysis: also known as smart farming.

Renewable energy

What also contributes to the small ecological footprint is the fact that farmers and horticulturists in the Netherlands are involved in the production of at least 42% of the renewable energy in the Netherlands. Many greenhouse horticulturists also use sustainable energy sources such as residual heat and solar energy. A total of 4.9% of all the energy in the Netherlands is used by the agricultural industry.

KP Holland is one of the thirty growers who have signed an agreement to participate in the geothermal project Trias Westland. If the drilling is successful, all the participating growers will get a connection to the geothermal energy coming from the Triassic layer, at a depth of 4 kilometres. This geothermal project for horticulture will be unique in the world.

In the past months, 65 companies have expressed interest and thirty growers have already committed themselves to this sustainable initiative. The total power for which the letters of intent were signed currently amounts to about 60 MW. One of the companies is KP Holland, a horticultural business in Westland that sees sustainability as one of its core values. A sustainable energy supply for the family business is therefore a logical step. KP Holland is a global supplier of young and flowering plants of Kalanchoe, Spathiphyllum and Curcuma.

According to Roy van der Knaap, manager of energy and technology, geothermal energy is one of the few alternatives to fossil fuels. The stock of fossil fuels is limited, it is bad for the climate and with the current global developments the delivery can sometimes be uncertain. "The project Trias Westland fits well with our company and philosophy. We embraced it wholeheartedly and full of enthusiasm."

Ceiling price

The participants will be closely involved in the development of the project and will become co-owner without having to invest themselves. The price that is paid by the participants is based on actual costs, including a reasonable compensation for the risk capital of the founders of the project. The fact that there is a 'ceiling price' offers more security for the participants.

According to the director of Trias Westland, Marco van Soerland, not all growers who have shown interest have signed the actual agreement. "Those who have not signed, may not be able to because they are in between two other geothermal energy initiatives and are forced to wait. But there was a lot of interest in the project and there still is now. "Van Soerland expects that the negotiations with all the parties will be finished in April.

New participants are still welcome, but speed is of the essence. "Applications can continue, but we will start shortly with the development of the different scenarios and therefore it is necessary that we know exactly who wants to join." Only after the exploratory drilling it will be clear how much heat will become available.

Combined drilling

In order to limit the (financial) risks of the exploratory drilling, a combined drilling is done. This means that first they will drill to the Lower Cretaceous-layer at a depth of 2 to 3 km. After examination of this layer they will continue to drill to the Triassic layer at a depth of 4 km. If the Triassic layer is unexpectedly found to be unsuitable for the extraction of geothermal energy, a Lower Cretaceous doublet will be realised. In which case, the purpose of the exploratory drilling - determining the suitability of the Triassic layer – is achieved, costs are reduced and a profitable Lower Cretaceous project will be realised.

If the Triassic layer is suitable, 30 to 50 growers can be connected to the geothermal heat source. If that is not the case, a Lower Cretaceous project will be realized and approximately 20 to 30 growers could make use of geothermal energy. In both scenarios, the most economical connections are realised first. Growers who are closest to the drilling site and whose neighbours have also joined the project have the best chances.

Dutch bell pepper producer 4Evergreen is considerably expanding its acreage in the Zeeland Smidsschorrepolder. The company of the brothers Grootscholte has asked the BOM Group to add 18 hectares of greenhouses to the existing 10 hectares of 4Evergreen in the same polder.

BOM Group is responsible for building the greenhouses and provides them with the newest technologies. One of these technologies is the double screen installation with the slip-in system from Peter Dekker Installaties. The expansion in the Zeeland-Flemish polder brings the total acreage of greenhouses of this pepper grower to 80 hectares. This makes 4Evergreen one of the largest producers of bell peppers in Europe. In addition, the company owns another several dozens of hectares in the Smisschorrepolder that can be built on in the future.

Residual heat and CO2

The reason that 4Evergreen has chosen to expand in the Smidsschorrepolder, near Westdorpe, is mainly because of the availability of residual heat and CO2, which is generated by the fertiliser plant Yara. The supply of these energy flows initially gave the horticultural area an energetic start. However, these developments were interrupted by the crisis, until the area started to revive again a couple of years ago.

Tomato grower Van Adrichem Nurseries established itself in the polder with 9 hectares of greenhouses, and the possibility to expand another 20 hectares. The Belgian United Vegetable Growers (VGT) is also building a company in the Autrichepolder with a total acreage of 30 hectares, which means that the polders in and around Westdorpe, except for some parcels, are nearly sold out.

'We should not depreciate the closed greenhouse', 'Greenhouse growers should rely less on feelings and more on knowledge' and 'In the greenhouse sector of 2050 gas is no longer relevant'. These were some of the remarkable statements that were made at the well-attended EnergiekEvent 2016 in Bleiswijk, where the 10th anniversary of Kas als Energiebron was also celebrated.

Looking back, Kas als Energiebron (Greenhouse as a Source of Energy), the innovation and action programme for energy efficiency and sustainability in the greenhouse horticulture sector, was found to be successful. The energy efficiency of the Dutch greenhouse growers has increased significantly, while the energy sources are becoming more sustainable. Especially thanks to geothermal and residual heat, wind energy, (semi-)closed greenhouses, diffuse glass, LED lighting and - the manual is in need of a reprint - Next Generation Cultivation.

Micro-controller

The best news of the EnergiekEvent was that the increased energy efficiency does not affect the quality or production. But it does require more data, knowledge and insight of the growers. "Before, there used to be one measuring unit on each hectare. In the future we want to change this to smaller units. Maybe even to micro-controllers for every plant, not only for the production, but also for the quality. For example, think of LED lighting to enhance certain plant components," says Sjaak Bakker, manager of Wageningen UR Greenhouse Horticulture.

Bakker outlined a future in which electricity will play a leading role. "We are rapidly moving towards an all-electric situation. Just look at electric cars, batteries and what's happening in LED lighting. They are already thinking about lighting through foils or glass cells."

Our CO2 supply should also be different in 2030 or 2050, Bakker said. "If we no longer burn gas in the future, where would we get our CO2 from? An example might be extracting CO2 from the air."

Closed greenhouses

Next Generation Cultivation is being succesfully applied in various crops, including tomato and gerbera. An estimated 15 to 20% of the Dutch growers is using this method. A lot of knowledge has been gained in closed greenhouses and during previous research, Bakker said. "In Next Generation Cultivation many things that were already developed have been put together: think of temperature integration, research on screens, air movement, etc."

The closed greenhouse is disappearing, it seems. But Wilco Wisse, chairman of Kas als Energiebron and staffmember of Lans Tomaten, thinks that closed greenhouses should not be depreciated. "We ourselves also have an Optima greenhouse of 1.5 hectares and we know better than anyone how difficult it is to make profits with it. It is actually a huge solar collector though, it stores excess heat of the summer and supplies it in the winter. Therefore, we should not depreciate the closed greenhouse.”

Sustainable future

Leo Oprel, currently working as a policy advisor at the Ministry of Economic Affairs - who is considered as the founder of Next Generation Cultivation at Wageningen UR - outlined a sustainable vision of Dutch horticulture, in which:

new greenhouses will look very similar to existing greenhouses

gas has been replaced by sustainable electricity and heat

virtually no chemical pesticides are used

the use of CO2 for growth is limited

knowledge is crucial

climate control will include energy and ventilation management

heat exchangers will become commonplace to transfer energy from the moist greenhouse air to the incoming drier air

cultivation is done with more humidity, with a very homogenuous greenhouse climate

light is the key for temperature control

the diffuse greenhouse roof transmits more light and there are more screens hanging above each other

super translucent greenhouses will determine the production - and the existence - in the winter

light will be flexibly captured above a certain level in the summer and will be available for energy storage

excess radiation is immediately absorbed without the greenhouse air heating up too much

assimilation lighting is used on the basis of the requirements of the plant

the artificial light is also dimmable because it works with direct current

Kas als Energiebron, the innovation and action plan for energy efficiency and sustainability in greenhouse horticulture of LTO Glaskracht Nederland and the Ministry of Economic Affairs, will continue until the end of next year. Both the greenhouse horticulture industry and the government want to continue with the program. The ministry of Economic Affairs wants to maintain the 50/50 cost sharing – but is still negotiating with LTO.

At the end, the participants visited the workshops and greenhouses at Wageningen UR/Delphy Improvement Centre, where they were informed of the latest research.

A delegation from a greenhouse horticulture community in the Belgian city of Kempen and representatives several government agencies visited a geothermal well and a cluster of horticulture firms in the Dutch province of IJsselmuiden. The Belgian representatives examined the feasibility of this source of energy in their own country.

Greenhouse horticulture is an important economic sector not only in the municipalities of Hoogstraten, Rijkevorsel and Merksplas, but also in the province of Antwerp, and one in which sustainability will remain a key issue in the next few years to come. A shared interest in sustainability is one of the reasons why these municipalities, together with the Flemish government, the Province of Limburg and various industry associations are looking into alternative sources of energy for heating their greenhouses. In the Dutch municipality of IJsselmuiden, located in the ‘Koekoekspolder’ greenhouse horticulture area, a deep geothermal well provides five greenhouse horticulturists with geothermal heat. The geothermal heat is extracted at a depth of approximately 1900 metres.

Great enthusiasm

Everyone present was given extensive information about the project. Aside from the technical aspects, which could also be applied to projects in Antwerp, several other critical success factors were extensively discussed. These included the risks associated with the realisation of the project, the complex financing issues and the current price of natural gas.

The Flemish delegation was informed that the project owes its success to the outstanding collaboration between the various stakeholders, the execution of a long-term vision on sustainable energy and the perseverance exhibited by the horticulturists and the project leader. The visit was received with great enthusiasm from the Flemish guests. They are all assured that they will be able to realise similar projects through collaborative efforts within the greenhouse horticulture industry in the province of Antwerp.

Economic importance

‘Not only is greenhouse horticulture of tremendous economic importance to the province of Antwerp, sustainability is also a key priority on our agenda,’ says Ludwig Caluwé, the Provincial Executive member for economic affairs. He joined the delegation of greenhouse horticulture municipalities on their visit to the geothermal well site, which enabled them to gain a clear insight into how sustainability and greenhouse horticulture can be aligned. Greenhouse horticulture and geothermal energy can support one another through the realisation of an energy cluster in a greenhouse horticulture area.

Houweling's Tomatoes in Camarillo, California has been showered with awards for its sustainable approach. Many of the techniques for saving water and energy are new to the American horticulture industry and a source of inspiration for fellow companies.

"Going green" can be a successful economic strategy that leads to sustainable growth, the jury said at the presentation of one of those awards. That accurately sums up the vision of Casey Houweling, owner of Houweling's Tomatoes. "What sustainability is to us is a combination of caring for our planet - which we will leave to our children - and commercially viable solutions for growing healthy, delicious tomatoes," says the grower.

In this family, the innovative entrepreneurial spirit is passed from generation to generation. His father, a Dutch immigrant, built a horticultural company in British Columbia with years of hard work. Son Casey continued where his father left off and now has locations in Canada and the USA. While the company may now be significantly larger, one thing has not changed: the ambition to be in the vanguard of sustainability and produce top quality tomatoes.

Semi-closed Ultra Clima greenhouse

The location in Camarillo has 125 acres of greenhouses, with around 40 acres' worth of the semi-closed type that have few windows that open and instead have air handling units to regulate the greenhouse climate. "This type of system makes use of many fans which requires considerable additional electricity," says Richard Vanderburg, energy and water conservation manager. "That is why we installed five acres of solar panels over the water basins in 2008. This was attractive because the State of California provides a 50% subsidy."

"What sustainability is to us is a combination of caring for our planet - which we will leave to our children - and commercially viable solutions for growing healthy, delicious tomatoes."

Until then, the heat required for the greenhouses had been provided by gas boilers, but that is not the most efficient use of energy. "With a combined heat and power (CHP) system, because it simultaneously produces heat, electricity and CO2, you can utilize practically 100% of the energy. There is no longer any waste. We have Casey Houweling's enthusiasm to thank for the fact that we now have three 4.4 MW CHP units."

The cogeneration technique is still not all that common in the USA. The technique has been used for the combustion of gas extracted from garbage dumps and waste-water treatment, but it is virtually unheard of in horticulture.

Selling back to the grid

Purchasing the CHP system was the easy part. "Much harder were the negotiations to sell the generated electricity back to the grid. The regulatory environment was difficult. It took us three years to win that battle," says Vanderburg.

Another challenge was the interplay of boiler, combined heat and power units, solar panels, heat storage and assimilation lighting. "At certain times, exporting to the grid has a strong commercial position - in the summer the peak rate period is between noon and six in the evening - so we run the CHPs at their maximum and we can make good use of the produced CO2 at that time. Export is therefore given priority over our own use, for lighting as an example. The heat is stored in the buffer. The buffer charging must be done in such a way that the CHPs can run at full capacity during the lucrative hours. If, on the other hand, the heat demand cannot be met entirely with the CHPs, the boiler has to kick in," he says.

"We harvest rainwater from the roof, and we collect the condensation water from the CHPs. We don't waste a drop here."

Designing a system to control all this is very complicated, and therefore Houweling's called in world-class specialist Priva. The choice was made for a very user-friendly solution. Everything is presented graphically on the computer screen; this insulates the operator from most of the complex process coordination taking place in the background. "There is very little that has to be done manually," the manager realizes. "And the system stores all the data, which is useful because we not only need it for our own analyses but also for the energy subsidy. Working with Priva has been a pleasure. Project engineer Richard Zeeuw found smart solutions to meet all of our needs and made it very easy to operate." To integrate all the new technologies, John van der Wilk of Priva Business Solutions was closely involved in discussions with the local power company and the contractor.

Water scarcity

Houweling's is not only very progressive in its approach to energy but also in how it handles water. "Water scarcity is a major and ever-growing problem in California. We do have our own well, but we are only allowed to extract a limited amount of groundwater," says the manager. "Therefore we capture as much water as possible. We harvest rainwater from the roof, and we collect the condensation water from the CHPs. We don't waste a drop here."

The plants get the water they need: with the Priva computer we can dose the water based on the measured evaporation, enabling us to provide the exact amount of water needed. The evaporation is measured through continuous monitoring of the weight of the substrate mats. The drain water is recirculated to the extent possible, and potential contamination issues are ruled out by disinfecting the return water before reuse.

This efficient use of water has also played a role in the sustainability awards the company has received. "We do everything possible in the current situation," tells Vanderburg. "But we are already pursuing a new initiative: obtaining purple water from the treatment plant three miles away. That water is currently being discharged to the ocean after treatment, but we could put it to good use. With reverse osmosis we can make it suitable for cultivation. In time, this could completely offset the water we currently extract from the well."

Drilling commenced at the end of 2015 for a second geothermal well in the Californië horticultural area located just to the northwest of Venlo in the Netherlands, 1½ kilometres from the geothermal well operated by greenhouse horticulture firm Wijnen Square Crops. Sustainable heat was sought - and found - at 2,500 metres below the surface, and will be used to heat existing and newly built greenhouses in the surrounding area.

Construction of the second doublet was in the hands of property developer Californië BV and three horticultural firms: namely those belonging to Frank van Lipzig, Roland Gielen and the van Leeuwen brothers, Thomas and Jordan. Drilling operations started on 3 December 2015. Exactly two months later the production well was tested. The result was a maximum yield of 375m3 per hour, at a temperature of 80° C.

The growers involved in the project are ecstatic. The decision was made immediately to start drilling an injection well. If the results obtained here are just as good, the three horticulture firms will be able to turn off their gas supply almost entirely. Not only that, sufficient geothermal heat will be available for the adjacent 20-hectare plot of land as well.

Beyond expectation

The injection well will be tested in March. The above geothermal system will be constructed in spring, and the supply of geothermal heat is expected to commence in the course of next autumn. The heat will be distributed to three horticulture firms, at which tomato and cucumbers are grown and that cover an area of 26 hectares collectively. The costs associated with drilling the wells and the installation of the pipes amount to 13 million euros.

Drilling operations are executed by T49 at KCA Deutag, the company responsible for drilling the geothermal wells operated by the Aardwarmte Vierpolders Collective. The necessary mining engineering expertise is being provided by WEP (Well Engineering Partners) and the project is being supervised by Radboud Vorage, the agency that was also in charge of the Koekoekspolder Project.

The Collectief Aardwarmte Vierpolders geothermal heat well has been taken into operation. Although this is a few months later than planned, Paul Grootscholten has nothing to say about the cause of the delay except that: ‘you can make plenty of plans, but there are always surprises.’

The well is currently producing a temperature slightly above 80°C. The secondary water is further heated by another 5°C, using the gas that is emitted as a by-product. The collective’s horticulture systems are now being adjusted to send the cooled-down water to the heat exchangers at the lowest temperature possible. All systems and the new regulatory mechanisms will be tested extensively during the next few weeks to come.

Test run

‘It is our goal to be able to operate at minimum capacity throughout the month of February, with a view to achieving a constant temperature regulation. We expect to be able to increase this in March, and to see how everything will respond,’ continues Grootscholten. During the ‘Kom in de Kas 2016’ event on 2 April a big part of the geothermal well site will be accessible to the public.

Collectief Aardwarmte Vierpolders is an initiative launched by eight horticulturists on an area covering 50 hectares of greenhouses. Drilling operations started in the summer of 2015, and the first hot water was pumped up to the surface on 12 August. The anticipated capacity of 17 MWth in geothermal heat will be enough to satisfy the heating demands of all eight affiliated potted plant and vegetable growers.

On 21 January 2016 a seminar was held at Priva in De Lier with the title ‘Geothermal energy, how difficult can this be?!’ Geology and engineering, as well as all the financing, success factors, benefits and risks associated with geothermal projects, were discussed extensively during the seminar.

Coen Leo, manager at PanTerra Geoconsultants, has many years of experience in geology. He explained why you can’t simply start drilling at random locations. He summarised the numerous risks in the fields of geology, engineering and operations and discussed how these could be kept in check. According to Leo, there are abundant opportunities in the Westland and Oostland regions for new geothermal projects. ‘The 70 megawatts that six working doublets can currently produce could be increased to 324, based on the available space below ground.’

Peter de Vreede, a geothermal heat specialist at Flynth, zoomed in on the organisational and financial factors and risks associated with geothermal heat. ‘As a grower, you need neighbours who will join you in setting up such a large-scale project. The project organisation and management of a geothermal heat cluster are key success factors.’ With regard to finances, it become clear that SDE Renewable Energy Production Incentive programme was highly relevant, while the MEI Market Introduction Energy Innovations programme will no longer apply to geothermal heat.

Frans-Peter Dechering, general manager at Priva, appealed to growers to stop focusing exclusively on the financial side of the matter. ‘Customers, society and nature are factors that cannot be overlooked. Consider the possibility of supplying the residential market with geothermal heat. Another factor associated with geothermal heat is its smaller carbon footprint. Besides this, it will help us decrease our reliance on oil.’

‘Not geology, but a crystal ball’

Jos Scheffers spoke of his experiences with the Green Well Westland project, a geothermal heat well to which ten growers are connected. ‘You can’t rely on geology; it’s more like gazing into crystal ball: the initial results remain unpredictable for a very long period of time,’ according to the entrepreneur. ‘You never know in advance what your flow rate per m3 per hour will be.’ Nevertheless, Scheffers is highly satisfied with the ultimate result. ‘Until today, this project has covered six years in which we have had to deal with numerous surprises. However, if asked, I would gladly do it all over again.’ He would, however, spend a little more time on choosing his materials. ‘You call in external advice because you don’t have the expertise you need. Based on what I know now, I would have made different choices.’

The seminar’s organisers PanTerra, Flynth, Priva and the Platform for Geothermal Energy look back in satisfaction at a successful event, with a full hall and plenty of interaction and in which a great deal of knowledge was shared.